Pregnant ? When could it have happened?

Hi everyone, my husband and I have a feeling we are pregnant with our 2nd child. We have yet to take a pregnancy test (we will 8/23 when he gets back from out of state work conference) but I am very curious on when it could’ve happened

Referring to picture:

•red= my period

•full heart= sex

•full heart with circle= sex w cumming inside

I would love some feedback! Thank you in advance 🫶🏼

Also does anyone else track your period like this? Or am I just crazy? 😂